In multi-frame presses of the aforedescribed type for the production of pressed board, i.e. chipboard, fiber board or particle board in which wood particles, pieces or fibers are pressed together and generally bonded together with the aid of an adhesive which can be activated by an elevated temperature produced in the press, the pressing usually is effected between upper and lower press plates and the press can have a bed plate and a head plate which can form press plates as well. In a continuous press steel belts usually carry the mat to be pressed between the press plates and, where required or desired, arrays of rollers may be interposed between each belt and the upper and lower plate.
The press support can be comprised of a plurality of frames as noted with each frame having a pair of lateral shanks or press limbs connecting together an upper horizontal frame limb and a lower horizontal frame limb. The upper and lower frame limbs may be referred to as upper and lower beams and generally provide mounting surfaces at the head portion and foot portion of the frame upon which the press plate or bed or the head plate of the press can be braced or supported and/or against which a piston-and-cylinder arrangement can be braced or fastened to enable at least one press plate, bed or head to be displaced to compress the mat between the pressing surfaces.
It has been proposed in the past to subdivide the press frames and thereby form two frame halves which can be connected together.
Such presses utilize press frames which are commonly designed for large presses and very large presses like, for example, 12 foot presses and create significant transport costs when the parts of the press have to be moved from the manufacturing site to an erection site. With the largest presses, namely, multi level presses in which the frames are subdivided vertically, the frame segments are very long and the subdivision of the frame is normally effected in the regions of the head part or the foot part of the individual frame. In these regions, which take up the bulk of the pressing force, special configurations are required for frame stability. For example, connecting flanges have had to be welded at the separations of the frames (see, for example, DE 44 41 063).
In such embodiments, the transport problems are enhanced not only because of the size of the pieces which must be transported but because the weight of the pieces greatly increases the individual frame weight and the complexity of the frames at the junctions of the parts thereof increases the complexity of assembly. Furthermore, the bolt connections hitherto provided between the flanged portions of the frame head or frame foot of the divided frame are not free from disadvantages in stability of the frame in the liability for long term pressing operations, in shape stability and even overall durability, especially for multilevel presses.
A further disadvantage, apart from the greater weight of the press frame when it is assembled, such vertically divided frame constructions must be reinforced because by comparison with closed frame constructions, no corner moments can be activated.